今個星期天文台點解D預告可以......

今日由八點到宜家,
唔好話落雨,
仲一路好好太陽....

但今日天氣預報搵句「短暫時間有陽光」都無....

原帖由 cx734 於 2007-5-19 11:46 發表
今日由八點到宜家,
唔好話落雨,
仲一路好好太陽....

但今日天氣預報搵句「短暫時間有陽光」都無....

根據雷達圖，正有一廣闊雨帶移近香港.... 相信下午開始會下大雨了....

The thunderstorm will be coming; if one likes thunderstorm, one will not be too disappointed.

Return to the question, HKO replies the information not so accuaretely because the weather changes instantaneously.  For example, HKO stated that there is shower, but not sunshine, on 5/10 - 5/13/07, but what is happened finally?  There is sunshine on the 4 days, but no such shower happens.  What is wrong?

There was low air trough (lat, #232) in  Northern South China Sea, and there was high air ridge (har, #231-233) in Shouteast China.  Theorectically, the weather in Hong Kong should be lati-sunshine-tude-thunderstorm.  However, no shower was possible because the lat is not stronger than the har.  Finally, the lat destoryed first.  This is the idea to explain why there was no shower in Hong Kong on 5/10 - 5/13.  In fact, there was the sunny period from 5/6 to 5/18 (before the evening T-shower).

I beleive that sunshine and thunderstorm needs to be balanced in the same year; because there is too much sunshine, the thunderstorm happens perfectly in time. (Why?)

The story (Part 1, on 5/10, 5/11)
The group of cloud-thunderstorm: Where is the shower?
The group of sunshine: The shower (may be selected district) does not happen in HKO, so this states that the shower "does not
                                  happen".
The gods: Sorry, this is our fault...
hp7629: The weather changes instantaneously causes this ending, and nobody even gods can change this.  

(Part 2, 5/18 afterward)
The group of cloud-thunderstorm:  Thanks for the lati-thunderstorm, but where is it?
The gods: Oh, the thunderstorm is coming, see you later...
The group of sunshine: How about sunshine?
The gods: According to the scientific report, this seems not be possible because no shortly sunshine is allowed to mix with the
                shower (for example, on 5/5/07 ).  However, because the weather changes instantaneously, every situation
                may be possible. (The solution of #2)
hp7629: Therefore, because there is not another high air ridge that builds up, no next sunny period in Hong Kong next 7 - 12
             days.

(Part 3, 5/22 - 5/31)
The group of cloud-thunderstorm: We need any rain (and thunderstorm), but not sunshine.
The group of sunshine: We need lat, but not har within this May.
The group of cloud-thunderstorm: (say to the group of sunshine) (*20)
The group of sunshine: In fact, we have not discovered that the next har will appear within this May.

Solution to the board #2:  The shortly sunny does not appear because the weather in Hong Kong on 5/19 is thunderstorm.  In
                                       this case, HKO does not state the weather that includes the shortly sunny.
                                       In fact, if the weather is a rainny serious, then no shortly sunny is included.

Exception: If the weather is cloudy, and somewhat sunshine is possible, then the shortly sunny is valid.  For example, the
                weather is cloudy and shower (very little?!) in the morning on 5/10, then HKO represents cloudy because the
                shower is very weak.  If the shower were stronger, then HKO would represent as light rain (no-sunshine-shower).
                After that, because the sun shines, then HKO uses the shortly sunshine to represent the weather in the afternoon
                on 5/10.  Similarly as on 5/11 case, but there was more sunshine on 5/11 than that on 5/10.

Next, let us introduce a special case: if some day is holiday, then sunshine may be possible.
In some cases, this statement can be true while some cannot be true.  Why?
Because the situation is still unchange: according to HKO, there is shower next 7 - 12 days.
The sun does not shine anymore from 5/25 to 5/26, may be from 5/27 and 5/28???  Good luck!
The soutwest monsoon is defined as lat #234A in this case.  No har #235 has appeared yet.  Hence, the sunshine and shower can appear together, but har is irrelavent in this case.   



[ 本帖最後由 hp7629 於 2007-5-22 04:00 編輯 ]

近期也發覺預測有點問題，因為很多時實際最高氣溫比預測最高氣溫高三至四度。

原帖由 petcity 於 2007-5-19 10:18 發表

究竟搞乜？唔通玉兔惹的禍？

應該唔關個玉兔事，
玉兔距離唔好講香港，連華南沿岸都有返咁上下遠距離咁遠

天文台剛剛於1250發出雷暴警告

[ 本帖最後由 大聲公 於 2007-5-19 13:02 編輯 ]

Sorry for my fault; the correction has been made.  
P.S. if you press enter before you enter the essay, then the blank essay appears.


The latest information is now available on #4.

近期天氣預測誤差有點大

Take more example:

There was lati-sunny on 4/18 after the the cold front-lati-thunderstorm at night on 4/17/07.  What is the temperature on 4/18?

The highest: 28.3 degree C;
The lowest: 17.4 degree C;
The difference: 10.9 degree C! (*10)

Is it posible in Hong Kong?  I do not think so, because in normal case, the temperature difference in lati-sunny days is: 5 - 6 degree C in summer, and 4 - 5 degree C in any other 3 seasons.  Outside the range is abnormal: the difference < 4 means the weather in particular day is not equal to sunny; the difference > 7 means the weather changes instantaneously and very abnormal.